Development of Instrumented Composite Cylinders

Abstract

This paper describes a technique to fabricate instrumented composite cylinders made by the filament winding process and based on the insertion of Bragg grating sensors contained in an optical fiber, so that real time monitoring of the temperature and strain response can be made. The main advantage of this method is that, for the first time, the strain response of the wound layers as a function of time and temperature can be monitored during fabrication without alteration of the composite structure, since the sensor is a filament itself. The sensor data reveals the existence of several phenomena related to the manufacturing process and material response. The results show that during the curing stage of the fabrication of the composite cylinders there is a dimensional contraction without change in temperature which indicates that a material transformation occurs, and also that at the last stage there is a residual compressive strain which may affect the in-service behavior of the composite cylinder.